Document reader transport comprising a positioning guide which includes a track of magnetic material

ABSTRACT

In a document reader having a reading station and where a document is transported past the station on a platen along a path established by a cam. The cam comprises a serpentine guide attached to the platen and engaging a magnetic drive roller. Magnetic forces acting on the serpentine guide and the drive roller cause the platen to traverse a path defined by the guide configuration. To determine the direction of movement of the platen, a preceder roller is supported by the drive roller and engages the serpentine guide.

United States Patent Gingras et al.

[451 Apr. 25, 1972 DOCUMENT READER TRANSPORT COMPRISING A POSITIONING GUIDE WHICH INCLUDES A TRACK OF MAGNETIC MATERIAL William P. Gingras; Roy E. Van Der Linden, both of Rockville, Md.

Recognition Equipment Incorporated, Irving, Tex.

Filed: June 2, 1970 Appl. No.: 42,746

Inventors:

Assignee:

US. Cl. ..250/2I9 CR, 250/219 Q, 250/224 int. Cl ..G01n 21/30, 606m 7/00 Field of Search ....250/219CR, 224,52,5l.5,

[56] References Cited UNlTED STATES PATENTS 1,914,258 6/1933 Howey ..250/219 0 2,798,957 7/1957 Holden et a]. ..250/51.5

Primary Examiner.lames W. Lawrence Assistant Examiner-T. N. Grigsby AttorneyRichards, Harris & Hubbard [57] ABSTRACT in a document reader having a reading station and where a document is transported past the station on a platen along a path established by a cam. The cam comprises a serpentine guide attached to the platen and engaging a magnetic drive roller. Magnetic forces acting on the serpentine guide and the drive roller cause the platen to traverse a path defined by the guide configuration. To determine the direction of movement of the platen, a preceder roller is supported by the drive roller and engages the serpentine guide.

18 Claims, 13 Drawing Figures PATENTEDAPRZS I972 i 3,659.1 1O

saw 1 OF 4 66 INVENTORS: WILLIAM R GINGRAS F, G 2 ROY E. VAN DER LINDEN AT TUHNF YS PATENTEMPRZS 1972 3.65511 1 O of j 7/ M fil H8 7/ t WW3 INVENTQRSZ 7 WILLIAM R GINGRAS ROY E. VAN DER LINDEN F I G. I O

ATTORNEYS PATENTEDAPRZS I972 3,6591 10 saw 3 OF 4 7O IOO 96 98 so a 72 LOGIC B6 CIRCUIT FIG. 9 FIG. 9A

PATENTEDAPRZS I972 3.6591 10 SHEET Q BF 4 /88 (L {/20 76 m C 1 c v //22 j Q I24 80 I04 94 FIG. 7 L

I38 K73 I I260 72;;-

lN VEN TOR S WILLIAM P. GINGRAS ROY E. VAN DER LINDEN ATTORNE (S DOCUMENT READER TRANSPORT COMPRISING A POSITIONING GUIDE WHICH INCLUDES A TRACK OF MAGNETIC MATERIAL This invention relates to document reading, and more particularly to document reading by means of a moving platen.

Many complicated and sophisticated document readers are commercially available for sensing infonnation recorded on a document and converting it into processable data. In one form of a document reader, a document to be read moves along a straight path and a reading head moves transverse to this path to completely read all lines of information on the moving document. Another form of document reader includes a transport to deliver a document to be read to a reading station. At the reading station, a matrix of light responsive sensors responds to the document information. In such reading machines, the scanning action is performed electronically. Machines using either of the above two techniques tend to be complicated and expensive pieces of equipment. For high speed and large volume document reading, such complexity and expense is easily justifiable. For applications where a relatively smaller number of documents is to be read, a simpler and less expensive reading machine is preferred.

An object of the present invention is to provide a document reader wherein a document to be read is transported past a fixed reading station. Another object of this invention is to provide a document reader wherein a document to be read moves past a fixed reading station on a moving platen. A further object of this invention is to provide a document reader wherein a document to be read is transported past a reading station along a path established by a cam configuration. Still another object of this invention is to provide a document reader wherein a document to be read is transported past a reading station on a platen along a path established by a serpentine guide engaging a drive roller.

In accordance with this invention, a document reader having a reading station for sensing information on a document includes a platform supporting the document to be read. The platform is universally mounted to move in two directions along a predefined plane past the reading station. A serpentine guide attached to the platform on the side opposite to the document engages a drive to position the platform with respect to the reading station. The path along which the platform moves is defined by the serpentine guide engaging the drive means.

In accordance with a more specific embodiment of the invention, a document reader having a reading station for sensing information on a document includes a platform universally mounted to move in two directions for the support of the document to be read as it moves past a reading station. The platform is universally mounted to move in a predefined plane along a path determined by a serpentine guide attached to the platform on the side opposite to the supported document. A drive roller engages the serpentine guide to position the platform with respect to the reading station in a travel pattern defined by the guide. The direction of movement of the platform as it traverses the defined travel pattern is sensed by a guide follower.

A more complete understanding of the invention and its advantages will be apparent from the specification and claims and from the accompanying drawings illustrative of the invention.

Referring to the drawings:

FIG. 1 is a perspective, partially in section, of a document reader having a document platform universally mounted to travel in a predefined plane;

FIG. 2 is a sectional view of the platform and drive unit taken along the line 2-2 of FIG. 1;

FIG. 3 is a perspective of a typical serpentine guide shown in engagement with a magnetic drive;

FIG. 4 is a side view of a preceder roller for determining the direction of movement of the document platform;

FIG. 5 is a top view of the preceder roller in engagement with a serpentine guide illustrating the roller position as the platform moves in one direction;

FIG. 6 is a top view of the preceder roller engaging an end section of the serpentine guide;

FIG. 7 is a top view of the preceder roller in engagement with a serpentine guide showing the roller position as the platform moves in a direction opposite to that illustrated in FIG. 5;

FIG. 8 is a top view of the preceder roller engaging the return section of the serpentine guide;

FIGS. 9 and 9A illustrate an overshoot and return guide for the serpentine cam of FIG. 3;

FIG. 10 shows an alternate embodiment of the serpentine guide of FIG. 3;

FIG. 11 illustrates a pinch roller drive mechanism engaging a serpentine guide; and

FIG. 12 shows another embodiment of a positioning mechanism for the document platform of FIG. 1.

Referring to the drawings, a document 10 delivered to a paper carriage 12 from a document transport means 14 is to be read at a reading station 16. Typically, the reading station 16 may be a disc-type scanner having a disc 18 rotating on the drive shaft of a motor 20. Rotating the disc 18 causes a character 22 to be scanned by an optical system including the lens assembly 24. Light reflecting from the character 22 and transmitted through the lens assembly 24 is broken up by the rotating disc 18 and sensed by photodetectors in a reading head 26. A disc-type scanning reader is fully and adequately described in the U.S. Pat. No. 3,380,334.

With the reading station 16 mounted in a fixed position, the operation of the rotating disc 18 causes the character 22 to be read along one axis thereof. To read the character along a second axis, the carriage 12 is mounted to move in the direction of the arrow 28 along parallel rails 30 and 32. Additional lines of characters on the document 10 are read by moving the carriage 12 in the direction of the arrow 34 along a track 36.

As best illustrated in FIG. 2, the carriage 12 moves along the parallel rails 30 and 32 by means of canted rollers 38 and 40 engaging the rail 30 and canted rollers 42 and 44 engaging the rail 32. These rollers are affixed to the housing 46 of the carriage 12 by means of roller brackets. For the carriage 12 to move in the direction of the arrow 34, the rails 30 and 32 are part of a supporting frame including end members 48 and 50 interconnected by means of a cross rod 52. The end member 48 is supported on a roller 54 that engages a base plate 56. To accurately position the movement of the carriage 12 along the track 36, the end member 50 has a hollow tube configuration and includes roller brackets 58 and 60 at opposite ends thereof. Each of the roller brackets 58 and 60 has a multiplicity of rollers 62 mounted therein and engaging the track 36.

Driving energy to move the carriage 12 along a path indicated by the line 64 to pass characters on the document 10 under the reading station 16 is supplied by a drive motor 66 mounted to the underside of the base plate 56. The drive motor 66 rotates a cylindrical shaped permanent magnet 68 that extends through the base plate 56 and engages a cam guide 70. The guide 70'is attached to a bottom plate 73 on the underside of the carriage l2 opposite the document 10.

An important feature of the present invention is that the optical axis of the lens assembly 24 and the longitudinal axis through the permanent magnet 68 always coincide during the reading of the document 10. Thus, the location of the carriage 12 with respect to the reading station 16 is always known. This is in contrast to document readers wherein both the document and the reading station move simultaneously and slippage in the movement of either one of the two moving mechanisms will disrupt the known spaced relationship of the reading station and the document in such readers.

In one configuration of the guide 70, as illustrated in FIG. 3, an array of substantially U-shaped sections 71 are juxtapositioned to form a continuous path for reading parallel lines of characters on a document. The carriage is returned to a starting position by the track section 72 and the loop section 74 joining the U-shaped sections 71.

In operation of the carriage 12 as described, the guide 70 is made from a magnetic material, such as soft iron, to be magnetically attracted to and held in contact with the permanent magnet 68. The permanent magnet 68 is rotated by the drive motor 66 and through the magnetic forces produced by the magnet causes the carriage 12 to move in the direction of the arrow 28 along a path established by one of the U-shaped sec-v tions 71 of the guide 70. When the magnet 68 traverses the end of the first U-shaped section 71, the carriage 12 translates to the direction of the arrow 34. The magnet 68 then moves along the second straight part of the first U-shaped section thereby causing the carriage 12 to move along a path indicated by the arrow 28, in a direction opposite to the previous motion, along the rails 30 and 32. As the magnet 68 moves to the end of two joined U-shaped sections 71, it again moves the carriage 12 in a direction indicated by the arrow 34. This back and forth movement along the parallel rails 30-and 32 continues as the magnet 68 traverses the serpentine path of the guide 70. Each time the carriage 12 changes direction along the path of the arrow 28, another line of characters will be read at the reading station 16.

When reading a line of characters on the document 10, data signals from the reading station 16 must be correlated with the direction of movement of the carriage 12 along the rails 30 and 32. To determine the direction of movement of the carriage 12, a preceder roller 76 is supported by the permanent magnet 68. This roller will be automatically positioned ahead of the permanent magnet 68 against the advancing guide track section.

Referring to FIG. 4, the roller 76, which may be a ball hearing, rotates on a shaft 78 extending from a direction collar 80. The direction collar 80 has an interior surface configuration that mates with the tapered upper section of the permanent magnet 68. By mating the inner taper of the direction collar 80 with the outer taper of the magnet 68, sufficient friction forces will be developed between the mating parts to cause the direction collar to rotate with the permanent magnet. However, upon the roller 76 contacting any part of the guide 70, the direction collar 80 will be held in a fixed rotational position with respect to the guide 70. Thus, as the magnet 68 rotates in the bearings 82 and 84, the direction collar 80 rotates until the roller 76 comes into contact with the guide 70. The roller 76, therefore, is always positioned ahead of the permanent magnet with relation to the direction of advance of the carriage 12. With the roller 76 in contact with the guide 70, the collar 80 will be in sliding contact with the permanent magnet 68. Typically, the direction collar 80 may be of a plastic material which has a coefficient of friction great enough to produce the desired rotating motion but low enough to permit easy movement of the magnet 68 with respect to the collar 80.

To determine the direction of travel of the carriage 12 with the collar and roller assembly, two mirrors 86 and 88 are mounted to the circumference of the collar 80 displaced 90, as illustrated in FIG. 5. With the carriage 12 moving in the direction of the arrow 90, the direction collar 80 will rotate with the permanent magnet 68 until the roller 76 comes in contact with a section of the guide 70. When the collar 80 is in the position shown in FIG. 5, a light beam from a source 92 is reflected from the mirror 88 to a photodetector 94. At the same time, light from a source 100 will be diffused by the collar 80. Consequently, the detector 94 will be generating a light signal while the detector 98 has a dark signal output. A signal generated by the photodetector 94 is applied to a logic circuit 96 which also receives a signal from the photodetector 98.

Although shown only schematically in FIG. 5, the light sources 92 and 100 and the photodetectors 94 and 98 are mounted to the base plate 56 to be always in a fixed spaced relationship to the permanent magnet 68. When the logic circuit 96 receives a light signal from the photodetector 94 and a dark signal from the detector 98, it generates a direction signal indicating the carriage 12 is moving from right to left with reference to both FIGS. 1 and 5.

When a curved end section of the guide 70 engages the magnet 68, as illustrated in FIG. 6, the direction collar rotates with respect to the detectors 94 and 98 thereby interrupting the light output signal from the detector 94. During the time when the permanent magnet 68 is positioning the carriage 12 in the direction of the arrow 102, neither of the detectors 94 or 98 receives a light beam from their respective sources. In this position of the collar 80, a dark signal will be generated by both photodetectors 94 and 98 and the logic circuit 96 produces a signal to indicate that the carriage I2 is moving in the direction of the arrow 102.

After the magnet 68 has traversed the end section of one of the U-shaped sections 71 of the guide 70, the carriage 12 moves in the direction of the arrow 104 as shown in FIG. 7. Again, the roller 76 leads the permanent magnet 68 as the guide 70 advances in the direction of the arrow 104, Since the mirrors 86 and 88 are fixed to the circumference of the direction collar 80, they are now 180 displaced from the position shown in FIG. 5. Light from the source 92 is incident on the relatively dull surface of the collar 80 and is diffused thereby. The detector 98, however, receives a reflected light beam from the mirror 86 as produced by the source 100. Thus, the photodetector 94 produces a dark signal to the logic circuit 96 and the photodetector 98 produces a light signal.

The logic circuit 96 in turn generates a direction signal indicating that the carriage 12 is moving in the direction of the arrow 104.

When the guide 70 has advanced such that the permanent magnet 68 is at the end of a straight portion of a U-shaped section 71, the direction collar 80 rotates with the permanent magnet and neither of the mirrors 86 or 88 will reflect light from the light sources 92 and 100 to the photodetectors 94 or 98. The logic circuit 96 again produces a signal indicating that the carriage 12 is moving in the direction of the arrow 102. After the end portion of the U-shaped section has been moved around the permanent magnet 68, the direction collar 80 rotates into the position illustrated in FIG. 5.

When each of the U-shaped sections 71 of the guide 70 has moved past the permanent magnet 68, the track section 7 2, as illustrated in FIG. 3, of the guide 70 comes in contact with the permanent magnet 68, as illustrated in FIG. 8. As the carriage 12 moves along a path as established by the section 72, the mirror 86 will be reflecting light from the source 92 to the photodetector 94. At the same time, light from the source 100 will be reflected by the mirror 88 to the photodetector 98. Consequently, the detectors 94 and 98 will both be generating a light signal. The logic circuit 96 will then produce a direction signal indicating that the carriage 12 is moving in the direction of the arrow 106. This movement continues until the carriage has been returned to the starting position, as illustrated in FIG. 1..

The truth table for the outputs of the detectors 94 and 98 as the carriage 12 moves in the four possible directions is given below:

Truth Table of Carriage Direction Direction Arrow Number Detector Output 94 98 102 Light Dark 104 Dark Dark 106 Dark Light Light Light Referring to FIGS. 9 and 9A, there is shown a modification of the serpentine guide arrangement wherein an overshoot capture bar 108 is mounted at the end of the straight portions of the U-shaped sections 71 of the guide 70. The capture bar 108 is slidably mounted to the base plate 73 by means of retaining pins 110 and 112. A solenoid 114 connects to the capture bar 108 through a linkage 116 to move the bar between the positions shown in FIGS. 9 and 9A.

With the capture bar 108 in the position shown in FIG. 9, if the guide 70 escapes the pull of the permanent magnet 68, the momentum of the carriage 12 will cause the magnet to recapture the serpentine guide in the next U-shaped section 71. This results in the normal line by line reading of the document along the path as illustrated in FIG. 1 as identified by the numeral 64.

If, during the reading of a line of data from the document 10, an error is detected by the reading station 16, the solenoid 114 is energized to position the capture bar 108 as illustrated in FIG. 9A. As a straight section of the guide 70 moves away from the permanent magnet 68, the momentum of the carriage 12 will return the permanent magnet to the preceding line through one of the scallops of the capture bar. This will cause the reading station 16 to re-read the previous two lines. Upon returning the carriage 12 to the preceding line upon detection of an error, the solenoid 114 is de-energized, returning the capture bar 108 to the position illustrated in FIG. 9.

To minimize the possibility of the guide 70 escaping the magnetic pull of the permanent magnet 68, the guide may be modified as illustrated in FIG. 10. Each straight portion of the U-shaped sections terminates in a bulbous end 118. By terminating each of the straight portions with a bulbous end 118, the magnet 68 maintains a stronger magnetic attraction force to the guide 70 because the centrifugal acceleration is lower than with the sharp ends of FIG. 3. By use of the bulbous ends 118, a smaller magnet 68 may be used. By using the same size magnet 68 with the bulbous ends 118 as with the sharp end configuration, an additional margin of safety is provided to ensure that the guide 70 does not escape from the permanent magnet 68.

Referring to FIG. 11, there is shown an alternate method of driving the carriage 12 along the path 64. Attached to the bottom of the base plate 73 is a serpentine guide 120 in the form of a continuous path. This guide is similar in cross section to the guide 70 as illustrated in FIG. 3; that is, it would be constructed from flat strip stock set on edge to the base plate 73. To drive the carriage 12 along the path 64 with the guide 120, a pair of pinch rollers 122 and 124 are positioned on opposite sides of the guide. These pinch rollers are driven by a motor (not shown), and as they rotate draw the guide through the rollers. In this embodiment, it is not necessary that the guide 120 be made of a magnetic material since the pinch rollers 122 and 124 produce movement of the carriage 12 by means of friction as opposed to magnetic force attraction.

With the embodiment of FIG. 11, the spacing between subsequent lines read on the document 10 is determined by the pitch of the serpentine guide 120. This is a variation from the drive technique illustrated in FIG. 3 where the character line spacing is determined by the diameter of the permanent magnet 68 and the spacing between adjacent U-shaped sections of the guide 70.

Referring to FIG. 12, there is shown still another embodiment of a drive mechanism for moving the carriage 12 to scan parallel lines of printed data. Attached to the underside of the base plate 73 is a series of wedge-shaped guide sections 126. These guides extend the width of the plate 73 with adjacent sections extending beyond the edge of the previous section. To drive the carriage 12 back and forth to read the parallel lines of data, a pair of drive rollers 128 and 130 are mounted to rotate on an axis parallel with the leading edge of the wedge-shaped guides. The roller 128 is driven directly from a drive motor 132 and the roller 130 is driven through spur gears 134 and 136 from the output shaft of the motor. With this arrangement, the roller 128 rotates in one direction and the roller 130 rotates in the opposite direction.

In operation of the embodiment of FIG. 12, the base plate 73 is urged in the direction of the arrow 138 forcing the wedge-shaped guide 126a against the roller 128. The roller 128 engages the leading edge of the wedge-shaped section 1260 and moves the plate 73 in the direction of the arrow 140. When the roller 128 passes the edge of the section 126a, the plate 73 is indexed in the direction of the arrow 138 until the roller 130 makes contact with the wedge-shaped section 126b, as illustrated in dotted outline. Since the roller 130 is rotating in the reverse direction from the roller 128, the plate 73 will move in the direction of the arrow 142. When the roller passes the end of the leading edge of the wedge-shaped section 126b, the plate 73 is again indexed in the direction of the arrow 138 until the roller 128 contacts the leading edge of the section l26c. The plate 73 moves in the direction of the arrow 140, as explained.

Upon completion of the reading of data on a document 10, the plate 73 is returned to its starting position with the carriage 12 in a position to accept another document for reading. With the embodiment of FIG. 12, the rollers 128 and 130 may be permanent magnets and the wedge-shaped guide sections 126 of a magnetic material. Alternatively, the rollers 128 and 130 may be a rubber that drives through frictional contact with the leading edges of the wedge-shaped guide sections 126.

Although the various embodiments of the guides previously described produce a parallel line reading pattern, the invention is not intended to be so limited. One of the features of the transport system described is that the reading path may be tailored to the data arrangement on a particular document. This tailoring is accomplished by substituting a particular guide pattern for the parallel line pattern described.

While several embodiments of the invention, together with modifications thereof, have been described in detail herein and shown in the accompanying drawings, it will be evident that various further modifications are possible without departing from the scope of the invention.

What is claimed is:

1. In a document reader having a reading station responsive to information on a document, comprising:

a platform mounted to move in a predefined plane and supporting a document to be read,

a guide including a track of a magnetic material attached to said platform on the side opposite the supported document, and

drive means engaging said guide to position said platform with respect to the reading station along a path defined by said guide.

2. In a document reader having a reading station responsive to information on a document as set forth in claim 1 wherein said guide includes a plurality of adjacent wedge-shaped sections attached to said platform on the side opposite of the supported document, and said drive means includes a pair of rollers rotating in opposite directions, one of said rollers engaging alternate wedge-shaped sections and the other of said rollers engaging the intermediate sections.

3. In a document reader having a reading station responsive to information on a document as set forth in claim 1 wherein said drive includes a continuous track defining the travel pattern of said platform, and

said drive means includes a pair of pinch rollers engaging said track on opposite sides thereof to cause said platform to be positioned in accordance with the outline of said track.

4. In a document reader having a reading station responsive to information on a document as set forth in claim 1 wherein said drive means includes:

a cylindrical shaped permanent magnet engaging said track,

and

motor means for rotating said permanent magnet to cause said platform to be positioned in accordance with the outline of said track.

5. In a document reader having a reading station responsive to information on a document as set forth in claim 4 wherein the travel pattern of said platform is determined by the outline of said track and the diameter of said permanent magnet.

6. In a document reader having a reading station responsive to information on a document as set forth in claim 1 wherein said drive means includes a magnet engaging the track.

7. In a document reader having a reading station responsive to information on a document as set forth in claim 6 wherein said track includes a plurality of substantially U-shaped sections juxtapositioned tocause said platform to travel in a pattern for reading parallel lines of characters on a document.

sive to information on a document as set forth in claim 9 including means for positioning said capture means from a line advance position to a line re-read position.

11. In a document reader having a reading station responsive to information on a document comprising:

a platform mounted to move in a predefined plane and supporting a document to be read,

a magnetic guide strip attached to said platform on the side opposite the supported document,

' drive means engaging said guide strip to position said platform with respect to said reading station in a travel pattern defined by said guide, and

means for generating an output signal related to the direction of movement of said platform and the travel pattern defined by said guide.

12. In a document reader having a reading station responsive to information on a document as set forth in claim 11 wherein said means for generating a signal related to the direction of platform movement includes:

direction collar means mounted to rotate with said drive means,

preceder means attached to said collar and engaging said guide to hold said collar in a position determined by the direction of travel of said platform, and

detector means positioned to be selectively energized as said collar assumes selected positions and generating a direction identifying signal.

13. In a document reader having a reading station responsive to information on a document as set forth in claim 12 wherein said detector means includes a pair of photodetectors.

14. In a document reader having a reading station responsive to information on a document as set forth in claim 13 including a mirror pair fastened to said collar for reflecting light to said photodetectors in a pattern controlled by platform movement.

15. In a document reader having a reading station responsive to information on a document as set forth in claim I2 wherein said guide is a track of a magnetic material.

16. In a document reader having a reading station responsive to information on a document as set forth in claim 15 wherein said drive means includes:

a cylindrical shaped permanent magnet engaging said track and supporting said collar, and

motor means for rotating said permanent magnet to cause said platform to be positioned in accordance with the outline of said track.

17. In a document reader having a reading station responsive to information on a document as set forth in claim 16 wherein said metal track comprises a plurality of substantially U-shaped sections juxtapositioned to read parallel lines on a document.

18. In a document reader having a reading station responsive to information on a document as set forth in claim 17 wherein the travel pattern comprises a series of parallel lines and the spacing between the series of parallel lines is determined by the U-shaped sections of the track and the diameter of said permanent magnet.

* YIK 

1. In a document reader having a reading station responsive to information on a document, comprising: a platform mounted to move in a predefined plane and supporting a document to be read, a guide including a track of a magnetic material attached to said platform on the side opposite the supported document, and drive means engaging said guide to position said platform with respect to the reading station aLong a path defined by said guide.
 2. In a document reader having a reading station responsive to information on a document as set forth in claim 1 wherein said guide includes a plurality of adjacent wedge-shaped sections attached to said platform on the side opposite of the supported document, and said drive means includes a pair of rollers rotating in opposite directions, one of said rollers engaging alternate wedge-shaped sections and the other of said rollers engaging the intermediate sections.
 3. In a document reader having a reading station responsive to information on a document as set forth in claim 1 wherein said drive includes a continuous track defining the travel pattern of said platform, and said drive means includes a pair of pinch rollers engaging said track on opposite sides thereof to cause said platform to be positioned in accordance with the outline of said track.
 4. In a document reader having a reading station responsive to information on a document as set forth in claim 1 wherein said drive means includes: a cylindrical shaped permanent magnet engaging said track, and motor means for rotating said permanent magnet to cause said platform to be positioned in accordance with the outline of said track.
 5. In a document reader having a reading station responsive to information on a document as set forth in claim 4 wherein the travel pattern of said platform is determined by the outline of said track and the diameter of said permanent magnet.
 6. In a document reader having a reading station responsive to information on a document as set forth in claim 1 wherein said drive means includes a magnet engaging the track.
 7. In a document reader having a reading station responsive to information on a document as set forth in claim 6 wherein said track includes a plurality of substantially U-shaped sections juxtapositioned to cause said platform to travel in a pattern for reading parallel lines of characters on a document.
 8. In a document reader having a reading station responsive to information on a document as set forth in claim 7 wherein the end of two juxtapositioned sections terminates in a bulbous configuration.
 9. In a document reader having a reading station responsive to information on a document as set forth in claim 7 including capture means positioned from the ends of said U-shaped sections for guiding said permanent magnet from one U-shaped section to the other.
 10. In a document reader having a reading station responsive to information on a document as set forth in claim 9 including means for positioning said capture means from a line advance position to a line re-read position.
 11. In a document reader having a reading station responsive to information on a document comprising: a platform mounted to move in a predefined plane and supporting a document to be read, a magnetic guide strip attached to said platform on the side opposite the supported document, drive means engaging said guide strip to position said platform with respect to said reading station in a travel pattern defined by said guide, and means for generating an output signal related to the direction of movement of said platform and the travel pattern defined by said guide.
 12. In a document reader having a reading station responsive to information on a document as set forth in claim 11 wherein said means for generating a signal related to the direction of platform movement includes: direction collar means mounted to rotate with said drive means, preceder means attached to said collar and engaging said guide to hold said collar in a position determined by the direction of travel of said platform, and detector means positioned to be selectively energized as said collar assumes selected positions and generating a direction identifying signal.
 13. In a document reader having a reading station responsive to information on a document as set forth in claim 12 wherein said detector means inclUdes a pair of photodetectors.
 14. In a document reader having a reading station responsive to information on a document as set forth in claim 13 including a mirror pair fastened to said collar for reflecting light to said photodetectors in a pattern controlled by platform movement.
 15. In a document reader having a reading station responsive to information on a document as set forth in claim 12 wherein said guide is a track of a magnetic material.
 16. In a document reader having a reading station responsive to information on a document as set forth in claim 15 wherein said drive means includes: a cylindrical shaped permanent magnet engaging said track and supporting said collar, and motor means for rotating said permanent magnet to cause said platform to be positioned in accordance with the outline of said track.
 17. In a document reader having a reading station responsive to information on a document as set forth in claim 16 wherein said metal track comprises a plurality of substantially U-shaped sections juxtapositioned to read parallel lines on a document.
 18. In a document reader having a reading station responsive to information on a document as set forth in claim 17 wherein the travel pattern comprises a series of parallel lines and the spacing between the series of parallel lines is determined by the U-shaped sections of the track and the diameter of said permanent magnet. 